Method resolveShellOrExit

src/commands/completion.ts:42–74

* Resolve shell parameter or exit with error * * @param shell - The shell parameter (may be undefined) * @param operationName - Name of the operation (for error messages) * @returns Resolved shell or null if should exit

(shell: string | undefined, operationName: string)

   * @returns Resolved shell or null if should exit
   */
  private resolveShellOrExit(shell: string | undefined, operationName: string): SupportedShell | null {
    const normalizedShell = this.normalizeShell(shell);

    if (!normalizedShell) {
      const detectionResult = detectShell();

      if (detectionResult.shell && CompletionFactory.isSupported(detectionResult.shell)) {
        return detectionResult.shell;
      }

      // Shell was detected but not supported
      if (detectionResult.detected && !detectionResult.shell) {
        console.error(`Error: Shell '${detectionResult.detected}' is not supported yet. Currently supported: ${CompletionFactory.getSupportedShells().join(', ')}`);
        process.exitCode = 1;
        return null;
      }

      // No shell specified and cannot auto-detect
      console.error('Error: Could not auto-detect shell. Please specify shell explicitly.');
      console.error(`Usage: openspec completion ${operationName} [shell]`);
      console.error(`Currently supported: ${CompletionFactory.getSupportedShells().join(', ')}`);
      process.exitCode = 1;
      return null;
    }

    if (!CompletionFactory.isSupported(normalizedShell)) {
      console.error(`Error: Shell '${normalizedShell}' is not supported yet. Currently supported: ${CompletionFactory.getSupportedShells().join(', ')}`);
      process.exitCode = 1;
      return null;
    }

    return normalizedShell;
  }

  /**
   * Generate completion script and output to stdout